1. Field of Invention
The present disclosure relates generally to multi-tasking multiprocessor systems, and in particular, to discovery of a virtual topology in a multi-tasking multi-processor system.
2. Description of Background
In many mainframe computers, multiple processors are joined into a single unit, sharing the same name and data sets. Such multi-tasking, multi-processor systems represent an instance of a computer system running on one or more physical computers. These multiple mainframes may act as a single mainframe. Such systems can be broken down into LPARs, or logical partitions, each running a different operating system.
InfiniBand (IB), which is a form of System Area Network (SAN), defines a multicast facility that allows a Channel Adapter (CA) to send a packet to a single address and have it delivered to multiple ports. Each multicast group is assigned a unique address, and end-nodes that wish to participate in a multicast group do so via a ‘Join’ process initiated by the candidate participant with the Subnet Manager. The InfiniBand architecture is described in the InfiniBand standard, which is available at http://www.infinibandta.org and also hereby incorporated by reference.
Current multi-tasking multi-processor systems implement coupling technologies that are single threaded, and direct connected point-to-point links that support a single channel per physical link. The connections follow a pre-defined topology that not only describes the hardware connections, but also the software correlations. The hardware plays a significant role in helping to establish and maintain the link.
The transition of multi-processor multi-tasking systems that implement InfiniBand technology, with its greater virtualization of links, and potentially switched network, creates a number challenges including: the virtualization of the link to carry multiple distinct channels; finding and identifying the correct partner for the link; and exchanging enough information to guarantee that the connection can be made and maintained.